Add CNAME file for GitHub Pages

Change-Id: I13b1c6842ddd19d594609816ffc4c5541e1a9754
diff --git a/CNAME b/CNAME
new file mode 100644
index 0000000..7298e4c
--- /dev/null
+++ b/CNAME
@@ -0,0 +1 @@
+go.starlark.net